High quality nano-sized Al doped TiO2 powders were prepared using a DC plasma jet. Titanium tetrachloride (TiCl4) and aluminum chloride (AlCl3) were fed into the plasma flame as starting materials, and the ratio of Al to TiO2 was varied from 1 to 8 wt.%. We investigated the effect of process parameters on phase composition, particle size, and optical property by using XRD, SEM/EDX, TEM, UV/Vis spectroscope. The powders collected at the reaction tube were dominated by anatase. The size of synthesized powder decreased by increasing the amount of Al because doped Al species inhibited the particle growth. For the optical property, the absorption band of synthesized powders shifted from the UV region to the visible region according to the increase of the amount of Al dopant. (C) 2003 Elsevier B.V. All rights reserved.